Study of $e^+e^-\to\omega\chi_{cJ}$ at center-of-mass energies from 4.21 to 4.42 GeV

TL;DR

This study reports the first observation of $e^+e^- o ext{omega} ext{chi}_{c0}$ at specific energies, measuring cross sections and identifying a new resonance with a mass around 4230 MeV/$c^2$, distinct from known states.

Contribution

First observation of $e^+e^- o ext{omega} ext{chi}_{c0}$ and identification of a new resonance at 4230 MeV/$c^2$ with detailed cross section measurements.

Findings

$e^+e^- o ext{omega} ext{chi}_{c0}$ observed at 4.23 and 4.26 GeV

Resonance with mass $(4230 extpm8 extpm6)$ MeV/$c^2$ and width $(38 extpm12 extpm2)$ MeV

Cross section inconsistent with $Y(4260)$ line shape

Abstract

Based on data samples collected with the BESIII detector at the BEPCII collider at 9 center-of-mass energies from 4.21 to 4.42 GeV, we search for the production of $e^+e^-\to \omega\chi_{cJ}$ ($J$=0, 1, 2). The process $e^+e^-\to \omega\chi_{c0}$ is observed for the first time, and the Born cross sections at $\sqrt{s}$=4.23 and 4.26 GeV are measured to be $(55.4\pm 6.0\pm 5.9)$ and $(23.7\pm 5.3\pm 3.5)$ pb, respectively, where the first uncertainties are statistical and the second are systematic. The $\omega\chi_{c0}$ signals at the other 7 energies and $e^+e^-\to \omega\chi_{c1}$ and $\omega\chi_{c2}$ signals are not significant, and the upper limits on the cross sections are determined. By examining the $\omega\chi_{c0}$ cross section as a function of center-of-mass energy, we find that it is inconsistent with the line shape of the $Y(4260)$ observed in $e^+ e^-\to\pi^+\pi^-J/\psi$. Assuming the $\omega\chi_{c0}$ signals come from a single resonance, we extract mass and width of the resonance to be $(4230\pm8\pm6)$ MeV/$c^2$ and $(38\pm12\pm2)$ MeV, respectively, and the statistical significance is more than $9\sigma$.